Converting education at ICE USA

The AIMCAL-sponsored program featured key insights from some of the industry’s leading experts.

Converting education at ICE USA

Greg Hrinya, Associate Editor02.24.15

As part of ICE USA, AIMCAL sponsored a series of educational programs where industry experts took part in concurrent sessions designed to enhance and improve converting operations.

ICE USA event director Bob Chiricosta stated that attendance for the 2015 show grew by 15% compared to 2013. In addition, the nearly 40 educational conferences were well attended. Sessions focused on a variety of topics, including unwinding, crush cutting and slitting.

Selecting an Unwind and Unwind Splicer System
Bob Pasquale, president of New Era Converting Machinery in Paterson, NJ, USA, discussed the ins and outs of winding. His presentation touched upon methods of generating tension, web guiding practices and splicing options.

When it comes to a shafted unwind, manufacturers face lower costs and footprints. Shafted, he said, tends to be narrower than a shaftless unwind, as well. “Instead of putting the core shaft inside the core, the holders for the core are part of the unwind itself. This eliminates concerns for handling the shaft,” Pasquale said.

Operators must then decide whether or not to operate with a constant or non-constant tension system. According to Pasquale, there are two ways to generate tension in the process: a braked system or a motor/drive. The braked system is less costly to purchase and install. At the same time, Pasquale said it is easier to operate with less maintenance. The argument for the motor/drive system revolves around tension range.

Bob Pasquale discusses winds and unwinds at ICE USA.

“They typically have greater total tension range than a braked system,” said Pasquale. “They’re good for use at low tensions, but you can use the motor/drive system to push the material off the unwind to maintain the low tension. They react very quickly, so they’re good for use at the end of rolls ... and they work well with roll acceleration. So if the force of accelerating the roll exceeds the web tension, the motor works.”

As the web exits the unwind, it can be guided manually or automatically. The methods of then joining the webs depend on the web materials and the process. Pressure sensitive tapes or adhesives can be used, and certain materials work best with certain methods of splicing.

‘The process might include tension, your splice might be subjected to moisture and it may be subjected to heat,” added Pasquale. “These are all things to consider when picking which method is right for your particular process.”

The two splices are lap and butt. Pasquale explained that a lap splice is easier to form and the tail end of the one roll overlaps the leading edge of the new roll. A butt splice involves the tale butting up against the leading edge of the new roll. Certain applications and web materials may call for different methods. The splice decision might come down to a manual or automated process, which can be determined by the type of material used.

“There are a lot of different design considerations for matching an unwind to your web process,” concluded Pasquale.

Shear cutting functions like a pair of scissors, whereas crush cutting is similar to a pizza cutter. As Benson put it, “slicing versus brute force.”

As with any method of converting or finishing, the two methods have advantages and disadvantages. Shear cutting tends to be more expensive and a faster process, although it deals with less abrasive materials, Benson said.

Crush cutting is typically used with adhesives, labels and tapes. Tougher materials like sand paper and rubber also lend themselves to this process. Knife axis and alignment play pivotal role. “In crush cutting, the center line of the blade of the top crush cutter has to be on the center line of the anvil roll,” Benson explained. “If it’s not, you will have issues.”

In force analysis, the axis of the blade and the degree of pressure are measured to ensure a more efficient process and longer blade life. “People say ‘I’m only off a little bit,’ but what’s a little bit?” said Benson. “If you’re off, you’re going to have an effect on the blade life and the blade holder.”

The wider the radius, the more pressure is needed to cut through the material, he said, adding that a smaller radius will usually have a shorter lifespan. A clean cut will often result in less dust, but the operator will be sacrificing blade life for edge quality.

According to Benson, the initial crush cutting should begin with the minimum pressure necessary to cut. If the cut is starting to diminish, increases can occur in small PSI increments. “You don’t start out at 35 and then jump to 60 (PSI),” said Benson. “You will go from 35 to 37, then to 39, until you get to where the blade doesn’t cut any longer and it’s time to change the blade.”

Benson added, “Troubleshooting involves checking the holders and the blade, as there should be very little lateral movement.”

Slitting and Static Electricity
Matt Fyffe, general manager and vice president of Meech International’s North American operation in Norton, OH, examined the effects of static electricity on the slitting process. Static electricity is defined as an electrical imbalance of charge that can exist on insulators and isolated conductors. The two main causes are friction and the separation of materials.

“Friction is basically your web cleaning contact with the roller,” said Fyffe. “It’s going to generate a lot of static charges. The more rollers you have, the more charges you’re going to generate.”

According to Fyffe, unwinding the roll generates a large amount of static electricity. The size of the charge is also important to Meech International, because the company will only attack the charge if it is causing a problem.

Speed is one of the greatest causes of static. Static electricity has gotten worse over the years due to the increasing speed capabilities of modern technology. Repetition and humidity can also affect static.

Nuclear eliminators, which involve Polonium 2.0, AC eliminators and pulsed eliminators are all used to counteract the charges. “What [nuclear eliminators] do is they actually create a perfect balance of positive and negative ions,” said Fyffe. “These systems are very easy to install, and they’re great for explosions requirements because there’s no chance of getting a spark to occur.”

Polonium 2.0 is only available for lease, as it is a regulated technology. Following a one-year period, the product must go back to the manufacturer, at which time it will offer a replacement. The main disadvantage is the cost.

Positioning of the materials–like rollers, the web and AC bars–can affect the static charge. Fyffe pointed out there are meters, however, that can measure the surface charge of the web. Ionizers can be applied to turret winders and sheeting processes, as well.